Sen. Hillary Rodham Clinton's presidential campaign has hired four more Nevada staffers, giving the Democratic front-runner the largest campaign staff in the state so far.

The campaigns of Sen. Barack Obama and New Mexico Gov. Bill Richardson have also staffed up in Nevada in recent weeks as the Democratic candidates prepare for a first-ever early Democratic presidential nominating caucus in the state.

The Clinton campaign said Monday it has hired political directors in Northern and Southern Nevada, a communications director and a deputy field director.

The Northern Nevada political director, Pam DuPre, is a former executive director of the Washoe County Democratic Party.

Alisa Naze, the Southern Nevada political director, previously was the finance coordinator for the failed gubernatorial campaign of Democratic nominee Dina Titus.

The communications director is another former Titus staffer, Hilarie Grey, who was head of communications for the University of Nevada, Las Vegas, before joining Titus' campaign last year.

Deputy Field Director Brian DiMarzio worked as the Nevada Democratic Party's canvass director during last year's election and previously worked for the AFL-CIO union in Nevada.

Last week, the Clinton campaign announced it had hired Robby Mook to run its campaign in Nevada. Mook is a longtime Democratic organizer who previously ran field operations in Maryland.

Clinton's Northern Nevada campaign chairwoman is former Nevada Attorney General Frankie Sue Del Papa.

"This shows that Senator Clinton is serious about Nevada, and she's dedicating the same resources here as in traditional states like Iowa and New Hampshire," Clinton's state chairman, Clark County Commissioner Rory Reid, said Monday.

Obama last month hired the former executive director of the Nevada Democratic Party, Alison Schwartz, as his political director here and David Cohen, who managed the failed congressional campaign of Jill Derby last year, as his deputy state director.

Richardson was the first to hire staff in Nevada. His Nevada campaign chairman is Reynaldo Martinez, a former chief of staff to Senate Majority Leader Harry Reid.

Richardson also has a Nevada communications director, Josh McNeil, and has field organizers for Northern Nevada, Southern Nevada and rural Nevada - Teresa Navarro, Javier Trujillo and Michael Tassone, respectively.